Aryloxide ions (Ar'O-) behave as C-nucleophiles towards diazosulfides (ArN=NSR; R = Ph, But) leading to unsymmetrical hydroxybiaryls (ArAr'OH) via C-C coupling. The reaction is particularly suited for the synthesis of terms which contain electron-withdrawing groups on the Ar moiety. The SRN1 mechanism is proposed on the grounds of experimental evidences.